Composite structure



Patented July 12, 1927.

UNITED STATES.

i aeaii PATENT OFFICE.

IRANGIS G. OKIE, O]? PHILADELPHIA, PENNSYLVANI A, .SSIGNOB T IINNIBOTL MINING & MANUFACTURING COMPANY, 01 ST. PAUL, MINNESOTA, A CORPORATION or mnmaso'ra.

courosrrn s'rnuc'rumi.

My present invention relates in general to the treatment of material, preferably in sheet form, and more particularly the treatment of material for the'purpose of forming or attaining composite structures, of which well known forms of abrasives such as what is commonly known as sand-paper is an example.

This application is a continuation in part of my applications, Serial Numbers 428,287

and 428,289.

Although I hereinafter disclose the practice of myinvention in connection with abrasives such as sand-paper, it will be understood that my invention, or certain features,

thereof, have a wider field of utility.

Composite structures of the abrasive type such as sand-paper or emery cloth comprise generally (a) a base ofsheet material, which.

i '20 may be felted as in .the case of paper'or woven as in the case of cloth, (1)) a more or less finely co'mminuated resistant material having abrading properties, such as garnet or corundum, and (o) a binder generally 1n the form of a glue which serves to bind the abrasive to the base,

The abrasive products as produced at present have as incidents certain features among which are (1) defect of desired drying qualities,

'dering them substantially inutile in the presence ofwater or moisture, (3) the tendency to premature pulverization or disintegration of the binder when exposed to nor- 5 mal atmospheric conditions and other undesired drying qualities, and (4) cracking, pith consequent exposure of the base, when ent. i The principal objects of my present invention are the provls'ion'of a binder which ,functions more efiiciently than an known to me; the rovision of a binder characterized by flexibility without cracking or other undesirable efiect; the provision of a binder characterized by extensibility and compressibility to accommodate itself to flexion of the base; the provision of a binder by means of which the desired adhesive action between it and the base is attained not only efliciently but also with a desirable degree of acceleration, and more particularly-the provision of a binder in which the drying 2) aflinity for moisture ren- Application madman 441922. Serial 110. 541,248.

action will be efiective fromthe contact surface between it and the base outwardly; the-provision of a binder in which the drying action will be eifective from the outer surface inwardly; the provision of a binder characteri'zedby a dryin action that'permits of handling the pro not with a minimum of delay. and more particularly such handlin without impairment of the superficles o the material; the provision of a binder characterized by an accelerated drymg action; the provision of a binder char-, acterized by a limitation of its drying action; the provision of an improved moistureproofing treatment for material, and especially material in a sheet form, and more particularly for causing a moisture proofing agent to penetrate into the material to an extent short of exudation on an adjacent surface thereof; the provision of a moistureproof composite abrasive structure; the. rovision of a binder having moisture-proo g functions, and the provision generally of I! an improved composite abrasive structure I and of a method of producing the same, together with such other objects and additional benefits and advantages as may hereinafter appear or be pointed out. a so In the employment of my present'invention for the roduction of sand-paper and the like (which I cite for purposes of example) I use as the base such a sheet of material (which may be paper) as will convens5 iently serve the employment contemplated,

and as the abrasive such comminuted' material (which may be crushed garnet) similarly' ada ted to serve the function in view.

It is esirable that the binder utilized on -have the functions and characteristics not only great of great mechanical strength and of binding strength, but also that it be non-hygroscopic, ermeative, moisture-resistant, easily wor ed, readily obtainable, inexpensive and-facilely applied. 4

I have discovered that gums of such types as are used in the manufacture of the bettergrades of varnish are peculiarly adapted for' thecattainment of these ends and that gums 1 0 such as kauri, copal, dammar are examples of these types. Gum dammar is preferred by me as best attaining the desired ends, viewed from certain aspects. v

' sociating with In preparing the binder for use, the gum is used in connection with a suitable vehicle which I prefer is of a ty e such as linseed oil or china wood oil, or reason which I will proceed to explain.

In applying a gum prepared with a vehicle such as linseed oil to one surface of a base of paper for example I have found that the action of the vehicle involves a penetration of the base by the vehicle, for example linseed oil, to a point which approximates the op osite surface of the sheet but falls short 0 actual exudation of the vehicle upon such opposite surface.

This results in a moisture-proofing of the material even against the absorption of moisture through the surface opposite to that to which the binder is applied, without at the same time defacing or otherwise undesirably aifecting such opposite surface.

This penetration by the vehicle, particularly when coupled with the use of the character of gum pointed out above, carries with it in such penetration a certain amount of finely divided. gum so that a coating and binding action is secured between the fibres or elemental portions of the base which thus substantially retards, if it does not entierly prevent, disintegration of the material of the base, in addition to preventing access of moisture through the base to the plane of contact between the base and the main mass of the binder material.

The efficient action of the binder may be enhanced in the manufacture of sand-paper ifthe binder is applied to the base b the use of pressure and the more or less ely divided abrasive is then applied in such a manner as to cause it to adhere to the binder.

In order to accelerate the adhesion between the binder and the base, I have discovered it desirable to use with the binder a modifying agent the action of which is to cause a desiccation of the binder initiated at the contact surface of the binder with the base and effective outwardly.

In my experience I have discovered that there are a number of materials having a metallic base which are useful for my pres ent purposes, that manganic oxides are peculiarly useful and that borate of manganese best combinates siccative energy with the desirable susceptibility to fine grinding.

Due to the relatively slow drying of binders generally, difiiculties are encountered in handling the structure, within a convenient period because of the soft and sticky character particularly of the exposed surfaces of the binder. This objection I mitigate by, asthe improved binder a substance the action of which is to produce an accelerated drying action effective primarily at the exposed surface and working inwardly, and for this purpose I incorporate in the binder a modifymg element peculiarly association Leaaeoo efl'ective in its action as an oxidizing agent on such vehicles as linseed oil and as a retarding agent with reference to the excess absorption of the vehicle by the base.

The substance I have discovered to be particularly adapted for this purpose is that carbonate of lead or white lead known to the trade as Dowdy White which is a new electrolytic process White lead and which in my experience is found to be more satisfactory than any other known form of carbonate of lead.

Whereas by itself the Dowdy White adds but relatively little strength to the binder, in in the binder with the borate of manganese it intensifies the action of the binder in holding the abrasive firmly against the base.

For intensifying the binding action of the binder and for intensifyin the drying action of the dryers, and at the same time accomplishing such ends by the employment of a material which is efficacious in holding the mineral elements insuspension without loss of siccative energy or reducing the relative fluidity of the material, I have discovered that it is advantageous to employ as part of the binder a paste dryer. This may comprise such mineral substances as sugar of lead and borate of manganese suspended in a resinous Vehicle but I find it preferable to form the paste dryer so as to have the minerals contained therein in the form of acetate of lead and resinate of manganese. I have found by experience that the paste dryer should be somewhat in the nature of cheesy butter, rather brownish grey color.

As an auxiliary in (l) accentuating the adhesion of the binder to the paper, (2) facilitating to a certain extent the spreading of the binder, and (3) modifying as desired softer, and of a light the consistency of the binder as is useful in cases where it is desired to render it more fluid, I have discovered that the use of a japan dryer is desirable. Such a dryer as that known as Schrack japan, owing to its relative freedom from resin, is preferable. One form of this contains shellac, red lead. litharge, manganese oXid, burnt umber, gum, linseed oil, and turpentine q. s.

In order to give the binder the desired body volumetrically considered I preferably employ a varnish consisting largely of linseed oil boiled until it reaches nearly a solid state. As far as feasible this should be as free as possible from glycerides and fatty acids.

The aforementioned gums, such as gum dammar are preferably employed in the form of a varnish which is substantially three parts Batavia Dammar, steam kettle inflted, with two parts kettle boiled linseed o1 While gum copal and gum kauri in certain respects make more substantial binders than gum dammar, as they will carry more oil and dry harder under certain conditions as may be useful for certain urposes, generally speaking the present re atively greater expense does not ordinarily justify their use for most purposes, which are well served by m dammar. Though I have hereinabove disclosed certain forms of useful dryers having various characteristics, and likewise intensifiers', I have discovered that where it is advisable that the siccative action thereof be limited,

' or at least retarded, under certain conditions,

verse effects, such as crackin of the binder,

or base, or loosening of one rom the other: and great resistance to water, and moisture generally.

Due to the character of binder for sand-- paper and the like which I thus produce, the

adhesion between the base, binder and abrasive is such that an auxiliary bonding matethe thinness ultimately desired.

rial, such as the outermost or top sizing coat, customarily found necessary, may for some purposes be dispensed with but may be appliedfor other purposes. Additionally, the

nature of the bond between the base binder and abrasive is such that sand-paper produced according to my present invention is characterized by freedom from clogging phen used on varnished and analogous suraces.

The rnaterials used by me as hereabove described may be varied in character so as to vary the characteristics 6f the binder from the stand-point of adhesiveness, non-hygroscopy, and flexibility. Where such variation in the use of materials is employedto produce, for instance, increased adhesion between the binder and the abrasive, such increase may be attained, though ossibl at a certain expense of its characteristic 0 flexi- 5 bility.

Due, however, to this ver same increased adhesiveness, one or more 0 the outer layers of the base may be removed as by the employment of a base'which involves the use of a built up structure having a number of plies, certain of which may be removed, or lfiy shaving off part of "the thickness of, the

ase. I

By this process I am enabled to obtain sand-paper characterized b extraordinary thinness and flexibility, in tlia form sand-paper and the like with a base so thin that such roduct could not be manufactured, if the ase originally used were of 'cle to t I am able to Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is:

1. The process for making sandpaper or the like which includes as steps thereof the employment bf a flexible sheet of fabric,

causing a moisture-proofing material to serve as a vehicle for a binding agent, applying said moisture-proofing material and agent as a coating to the sheet, applying a grit to said coating and allowing the vehicle to penetrate the sheet and carry with it a portion of the binding agent, whereby to form an abrasive article which is flexible, moisture-proof and tenacious when dry.

2. The processrfor making sandpaper or the like which includes as steps thereof the employment of a flexible, sheet of fabric,

causing a a moisture-proofing material to serve as a vehicle for a binding agent, applying said moisture-proofing material and agent as a coating to the sheet, applying a grit to said coating and allowing the vehicle to penetrate the sheet and carry with it a ortion of the binding agent and'causing a imitation of the penetration of the binder into said sheet, whereby to form an abrasive article which is flexible, moisture-proof and tenacious when dry. v i

3. The process for making sandpaper or the like which includes as steps thereof the employment of a flexible sheet of fabric,

causing a moisture-proofing material. to

serve as a vehicle for a binding agent, applying said moisture-proofing material and' agent as a coating tothe sheet, applying a grit to said coatin and allowing the vehicle to penetrate the s eet and carry with it a portion of the binding agent, and causing desiccation of the binder to be accelerated outwardly, that is, from the surface thereof in contact with the sheet, whereby to form an abrasive article which is flexible, moisture-grgpf and tenacious when dry.

. 4. process for making sandpaper or the like w ich includes as steps thereof the employment of a flexible sheet of fabric, causing a moisture-proofing material to serve as a vehicle for a binding agent, applying said moisture-proofing material and agent as a coating to the sheet, applying a grit to said coating and allowing the vehinetrate the sheet and carry with it a port on of the binding agent and causing desiccation of the binder to beaccelerated both at the surface vthereof exposed 'to the abrasive article which is flexible, moistureproof and tenacious when dry.

5. The rocess for making sandpaper or the like w ich includes as steps thereof the employment of a flexible sheet of fabric, causing a moisture-proofing material to serve as a vehicle for a binding agent, ap-

plying said moisture-proofing material and agent as a coating to the sheet, applying a grit to said coating and allowing the vehicle to penetrate the sheet and carry with it a portion of the binding agent and causin an intensification and limitation of the desiccation of the binder by the use of modifying agents, one of which is adapted to accelerate drying and the other of which is adapted to limit drying, whereby to form an abrasive article which is flexible, moistureproof and tenacious when dry.

6.'The process for making sandpaper or the like which includes as steps thereof the employment of a flexiblesheet of fabric, causing a moisture-proofing material to serve as a vehicle for a binding agent, applying said moisture-proofing material and agent as a coating to the sheet, applying a grit to said coating and allowing the vehicle to penetrate'the sheet and carry with it a portion of the binding agent, and regulating the thickness of the binding'coating and limiting the degree of penetration of'the sheet by the binder to prevent starving of the bond between the grit and said sheet, whereby to form an abrasive article which is flexible, moisture-proof and tenacious when dry.

-7. The new process of forming a new article of manufacture in the nature of sandpaper which includes employing a suitable base, applying to said base a binder layer characterized by flexibility, tenacity in the presence of moisture and friction, and causing said binder to penetrate into the base maaeoo for moisture-proofing the latter and for 'rendering the connection between the binder and the base durableiand limiting the penetration of said binder into said base.

8. The new process of forming a new article of manufacture in the nature of sandaper, which includes employing a suitable ase, applying to said base a binder layer characterized flexibility and tenacity in the presence 0 moisture and friction, applying pressure for causing said binder to penetrate into the base for moisture-proofing the latter and for rendering the connection between the binder and the base durable, applying a layer of grit to saidbindr and limiting the penetration of the base by said binder.

9. The process for making sandpaper or the like which includes as steps thereof the employment of a flexible sheet of fabric, causing a moisture-proofing material to serve as a vehicle for a binding agent, applying said moisture-proofing material and agent as a coating to the sheet, applying a grit to said coating and allowing the vehicle to penetrate the sheet and carry with it a portion of the binding agent, and causing desiccation of the binder to be accelerated inwardly, that is, from the surface thereof in contact with the air, whereby to form an abrasive articlewhich is flexible, moistureproof and'tenacious when dry.

In testimony whereof I have hereunto signed my name.

FRANCIS G. OKIE. 

